Process for making hollow rivets



July'10, 1928 .L. M. PERSONS PROCESS FOR MAKING HOLLOW RIVETS Original Filed 001:. 20- 92 0 size to be made. The next step in forming Patented July 10, 1928.

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,LAwRENoE /r. PERSONS, or onroneo, ILLnvoIs; Assreiion' ro'cooirnnnornio00 V .PANY, or onroneo, ILLINOIS, A CORPORATION or ILLINOIS.

rnoonss non MAKING noLL-ow Rivers. 1

#1923. Serial No; 840,823.

Original applieationiiled October. 20, 1920. Serial no. 418.308. Dividedand this application filed. may 23,

.My invention relates to split tubular rivets 5. The punch 9' and die 8 are so 'formed thatthe serrations 10, clearly indicated in Fig. 2, will be formed. At the same time the die 8 and punch 9,. will turn up the longitudinal edges 11 of the blank, as indiand the process for making the same.

One object of my invention is the provision of a simple and efficient tubular rivet capable of being easily expanded.

Another object of my invention is the provision of a tubular rivet internally threaded and capable of being expanded by adjusting a screw slightly .larger than the internal diameter of the rivet. t

A further object is the provision of a tubular rivet formed ofsheet material having the threads formed by stamping serrations in the sheet material before the latter is made into tubular form.

A still further object is the provision of a simple and efiicient method of making rivets, such as above referred to.

Other objects will appear hereinafter.

An embodiment of my invention is shown in the accompanying drawing, forming a part of this specification, and in which- Fig. l is a perspective view of a blank from which my tubular rivet is formed; 1

Fig. 2 is a similar view of the blank having the serrations formed therein and the longitudinal edges bent up;

Fig. 3 is a similar view showing the tubular rivet completely formed; I

Fig. 4c is an enlarged fragmental section of a motor core having a tubular rivet therein embodying my invention;

Fig. 5 is a fragmental section, more or less diagrammatically, illustrating the method of forming my improved rivet; and

Fig. 6 is an elevation, more or less diagrammatical, illustrating the finishing process of making my improved rivet.

This is a division of application, Serial No. 418,306, filed October 20, 1920.

My improved rivet has the advantage that it can be made very economically, much more so than wherethe tubular rivet must be made from a tube and internally threaded with dies.

In forming my rivet I first cutout a blank, such as indicated in Fig. 1, of the desired size to give a finished rivet in the the rivet is to place it in the position inclicated in Fig. 5 at 7 in a forming die 8.

The punch 9 is then brought down onto the blank 7 pressin it from its dotted line position to its ful line position shown in Fig.

cated in Fig. 2.,

The blank is next placed in'a die, such as indicated in Fig. ,6, and upon members 12 of such dies being forced of the arrows13 thevblank j v will be bent-from its full lineposition to that'indicated in dotted lines'insaid Fig. 6, thus completing the formation" of the split tubular rivet with its internal threads.

This rivet will be useful in many places and I find it particularly adaptable for securing the laminations of motors, dynamos,

in the directions and the like, together.

In Fig. t I have indicated the usual core laminations laof a motor which are provided with registering perforations 15 therein for receiving a rivet to secure such laminations together.

With

the use of my improved rivet the latter is placed in the perforations 15. and its @1108 riveted in the usual manner.

After the motor, or V the like, constructionsand threaded into the serrations 10 of myimproved rivet. In forming the serrations 10 it will be understood they are to be madeso that when finished the screw threads formedthereby will have the same pitch as the screws 16 to be used.

I preferably use screws 16 slightly larger than the internal diameter of the split rivets so that in forcing the screws into said rivets the latter will be expanded intoclose contact with the walls of perforations 15. The rough edges 18 of the rivet will also tend to cut into the walls of the perforations. l5 and facilitate holding the rivet against rotation while the screws 16 are being adjusted into or out of position. I

In Fig.4 I have indicated a screw 16 in each end of one of my improved rivets. This expands both ends of the rivet and binds all of the laminations together.

One

of the screws 16 holds the laminations 14 up against a shoulder 19 in the casing 20, and the other screw 16 holds the cap 17 inplace on the frame; .These parts may be arranged in other manners, an essential the screws-extend into the 7 thing being that rivet.

I claim 4 1. The method of forming tubular rivets comprising the step of stamping shallow serrations in one side only ofa piece of-sheetmaterial andthen bending the sheet material into a continuous arcto produce a tubular Y form with the serrations providing internal screw threads of a depth less than that of the thicknessofthe material.

2. The method of forming an expandihle tubular rivet comprising the step of stamping shallowserrations in one side'only of a rectangular piece of sheet'material, folding the 131608 of sheet 111ater1al'toproduce a tubula1'-"fo1"m with the said serrations provid ing internal threads of a depth less than that of the thicknessot the material.

3. Themethod of forming a tubular rivet comprising stamping" transverse serrations in a piece of sheet material and at the same time turningiup the longitudinal edges of such sheet material and thereafter bending said sheet intotubulariiorm so thatthe serinterior thereof.

Trations provide internal threads for the completed tubular rivet. 1 r

4. The method of forming a tubular rivet 1 comprising-cutting out a blank 0t sheet-material of proper form then-forming transverse serrations in one side only of the sheet mate piece and thereafter exerting-pressure on said bent edges'to bend said piece intocy lindriea'l formation with the-serrations at the In testimony whereof Ihave signed my name to this specification onthis 15th day of .May, A. 1923. i

' "LAWRENCE MpPERSONS; 

